In gas turbine engines a fuel supply system is provided to pump liquid fuel from a fuel tank into a combustor of the gas turbine engine. To remove foreign particles and other impurities, a fuel filter is positioned at an accessible point in the fuel supply system. Conventionally, the relatively cold incoming fuel from the fuel tank is used to cool the relatively hot oil scavenged from bearing, gearboxes, etc. and circulated in an oil system of the gas turbine engine. The fuel is in turn heated by the oil, thereby reducing the risk of icing in the fuel supply system. Therefore, a fuel-oil heat exchanger is conventionally used for the thermal energy exchange between the fuel supply system and the oil circulation system. The fuel-oil heat exchanger may also be positioned at a location in the fuel supply system and the oil circulation system which is convenient for access and inspection. Therefore, a combined fuel-oil heat exchanger and fuel filter arrangement may be used in a gas turbine engine to filter fuel while transferring thermal energy between the oil circulation system and the fuel supply system.
Accordingly, an improved fuel-oil heat exchanger is desirable for use in such a combined heat exchanger and fuel filter arrangements.